Which comes first, obesity or psoriasis? In children, at least, it appears to be obesity.
A new study of pediatric psoriasis cracked the chicken-or-the-egg question by investigating a group of overweight or obese children with psoriasis. Of the 27 children studied, 25—93 percent—were found to be obese or overweight at least two years before they developed psoriasis. Overweight was defined as having a body mass index (BMI) between the 85th and 95th percentile. Obese was defined as having a BMI in the 95th percentile or higher.
Results from the study, "Excess Adiposity Preceding Pediatric Psoriasis," were published last month in JAMA Dermatology.
Doctors noticed that the children they saw for psoriasis were often overweight, and tended to remain overweight throughout treatment. This observation led them to wonder whether children were overweight before they developed psoriasis. "I had a suspicion that the vast majority of kids would be heavy first," said Dr. Amy Paller, a co-author of the study.
Although the study involved a relatively small number of children, "the results were overwhelming," she said.
In addition to confirming Paller's suspicions, the study also shed new light on the importance of family history in the development of psoriasis and obesity. Researchers found that children with family members who were obese developed psoriasis an average of three years earlier than children whose families did not struggle with weight.
The family connection continues. Researchers also found that overweight children with psoriasis were more likely to have an immediate family member with psoriasis who also was overweight.
To Paller, the findings demonstrate the need for children and parents alike to make healthy lifestyle choices, like eating right and getting plenty of exercise.
"A lot of these kids come from families that have weight issues, which probably has driven some of the other psoriasis in the family," Paller said. "So there is good reason to make it a family deal, and encourage the entire family to get on the program with a healthy lifestyle."
Paller and her co-authors urge pediatricians and pediatric dermatologists to work together to further study the connection between obesity and psoriasis. A five-year study of at least 10,000 children would be needed to conduct a more extensive analysis, they note.